ARTHUR: NEW SPECIES OF UREDINEAE 375 
fortunately the morphological characters derived from the spores, 
and the geographical range, afford better diagnostic data than the 
host species. On the plains between the Mississippi River and 
the foothills of the Rocky Mountains a number of collections of 
aecia on Allium have been made, which may be placed under the 
name Aecidium alliicola Wint., that may or may not belong to 
Puccinia Winteriana Magn., having uredinia and telia on the 
grass Phalaris. From all that is known of their occurrence and 
structure, the connection seems probable, the Allium and Phalaris 
stages having been collected near each other, although no cultures 
have been made.+ Considerable study has recently been given to 
this group of rusts, and as a result the following key is introduced 
here to assist collectors. 
Key to American and European Allium rusts 
appar: smooth, 
ospores two-celled (Puccinia), often with mesospores. 
“Tellogpores strongly thickened above, 7—10n. 
Drediaduebaess with 6-8 scattered pores (not in 
America). P. Allii. 
Aecia present. 
Urediniospores with 6-8 scattered pores. P. Blasdalei, 
Ure Sip Tae with 3 or 4 equatorial pores (rarely e 
on Alliu P. Asparagi. 
Teliospores not or Aa thickened above, 3-5u. 
Autoecious, aecia amphigenous. 
lial stromata present, sometimes strongly 
veloped. 
wll with 8-12 scattered distinct 
pores. - granulis pora. 
Urediniospores with 7-9 scattered indistinct 
pores (rare in America). P. Porri. 
Telial stromata absent. 
Urediniospores with 6-8 scattered distinct 
pores. P. mutabilis. 
aaa orci aecia (on Allium) chiefly hypophyllous. 
Urediniospores (on Phalaris) with 4-6 scattered 
indistinct pores. P. Winteriana, 
Teliospores seal (Uromyees). 
Telia tardily naked. 
eat usainils with 6-8 scattered indistinct pores. U. aemulus. 
Telia permanently covered. 
Teliospores not thickened above U. aureus. 
Teliospores somewhat ciliata above. 
